The present invention is directed to the field of wireless networking, particularly as applied to different types of wireless networks having different implementation objectives. In a typical local area network (LAN), it is necessary for users to make a “hardware” network connection in which a client device (e.g. a personal computer system) is connected to a wire, which in turn is plugged into a socket for accessing a wired network. However, in using a wired LAN connection, a client device must be operated from a fixed position. This may be acceptable when using a stationary desktop terminal. However, if a laptop or handheld computer is used, it is necessary for the user to disconnect from the network when moving from place to place. Also, it cannot be assumed that a new location will have a network socket for reconnecting. This can be a significant limitation in enviromnents where it is important for a user to maintain a constant network connection.
Wireless local area networks (WLAN's) are becoming an increasingly popular alternative to a common wired LAN. In a WLAN, users make a wireless connection to the network. In this way, a user can move from location to location with a client device within a specified WLAN coverage area and maintain a constant connection to the network. This is highly advantageous since it enables the user to set up anywhere within a coverage area without requiring access to a network port. It also saves the user the inconvenience of fumbling with wires and plugs, while insuring continuous network connectivity for downloads and communications.
A client device can include a radio card having suitable radio circuitry for converting between electronic signals, internal to the device, and radio signals. The radio card also includes an antenna arrangement for exchanging radio signals with a wireless access point (AP). A typical AP also includes an antenna arrangement for exchanging radio signals with the client device, and radio circuitry for converting between the exchanged radio signals and electronic signals suitable to the wired network. Typically, such network signals are in accordance with the Ethernet protocol as specified in the IEEE 802.3 standard. Additionally, the radio signals are typically in accordance with the IEEE 802.11 wireless protocol.
In the marketplace, there are various WLAN implementations to satisfy various needs. Generally, a particular market implementation may require high-throughput connectivity where another may require extended radio range at the expense of throughput. For example, in the enterprise market, there may be a number of mobile clients such as laptop systems in a relatively small area, e.g. a conference room. In such an enterprise rollout, each mobile client might require high throughput, possibly for downloading audio-visual multimedia files. In such a case the clients would all be within relatively close proximity to the AP, so throughput would not be penalized by excessive distance from the AP. On the other hand, in a vertical market, wireless communications would be required over a large physical area, such as a warehouse or a large retail establishment, such as a department store. Low data rate wireless mobile client systems such as hand-held bar code scanner units would be employed for scanning inventory items and other such purposes, at locations physically remote from the AP. Hence in this market, low-throughput data is transferred over a large geographical distance, so extended signal range is required as opposed to high capacity.
Previously, it has been common to sell specific-type AP systems for each specific application: long range vs. high capacity. This has required manufacturers to produce different systems for each specific market. Providing distinct types of AP's contributes to overall expense, with manufacture, packaging, inventory, marketing, etc. Also, such systems do not offer flexibility to end-users having changing needs, where either throughput or range must be increased in a particular rollout at a later time after the original installation. Such systems are also not optimal in “hybrid” rollouts where throughput may be required in one portion of the coverage area and range is required in another. In these instances, the end-users would be required to add additional equipment to their WLAN, resulting in additional expense.